There are many ways to deliver a material to a person. For some materials, the delivery may be more difficult because the material may volatilize away once delivered to a person, or the material may adversely interact with other ingredients in a composition to reduce the level of the material. Also, it would be desirable to deliver a material to a person and have the material available when needed.
For personal care products, fragrance is used to provide a pleasant aroma to the product and the person. Fragrance longevity is desired to continue delivering the fragrance after the product has been applied. While fragrances can be encapsulated in various materials, there usually needs to be some mechanical action that breaks down the encapsulate to release the material. When the personal care product is an antiperspirant/deodorant, it would be desirable to release fragrance when needed during sweating.